


Bolt from the Blue

by raineynight713



Category: Katekyou Hitman Reborn!
Genre: M/M, flames as superpowers, superhero au
Language: English
Status: Completed
Published: 2018-06-24
Updated: 2018-06-24
Packaged: 2019-05-27 17:12:42
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,947
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15029324
Author URL: https://archiveofourown.org/users/raineynight713/pseuds/raineynight713
Summary: In which Tsuna saves the city, gets a dog, and goes on a hot date. Sort of.





	Bolt from the Blue

**Author's Note:**

  * For [eeveepkmnfan](https://archiveofourown.org/users/eeveepkmnfan/gifts).



> This is for KHR Rarepair Week 2018 Day 4, for the prompt Superhero AU. It's also a gift for eeveepkmnfan, who encourages all my weird ideas for KHR fic and really wanted some Tsuna/Byakuran.

Tsuna should have realized his day was going to be shit when he was woken up by a screaming argument in the hallway outside his suite. Vongola HQ was always noisy, it was the home of too many colorful personalities to be anything else, but people usually had the decency to at least go somewhere private first if the sun wasn’t up. (That had a lot to do with the first and last time Reborn was woken up in the middle of the night. No one involved had ever been the same. On the bright side, everyone could sleep peacefully now.)

Taking a moment to Harmonize with his surroundings, Tsuna identified the two arguers as Hayato and Belphegor. Why they were arguing (Something about cheese graters? Oh god, he really didn’t want to know.), and so close to his rooms when they both had rooms on the opposite side of the compound, was a mystery that he wasn’t touching with a ten foot pole. There were some things that just weren’t worth it, and getting between those two when they were ready to rip each other’s throat out was one of them.

They eventually wandered away, and the night was peaceful once again. Well, early morning; his clock read 3:00 AM. There was still plenty of time for him to catch some more sleep.  Unfortunately, Tsuna was left wide awake. Laying in bed, he considered getting up and turning the lights on, but kept talking himself out of it due to laziness.

It was a welcome distraction when his phone dinged with a notification from Irie that the city was facing a level eight threat, and they needed him to head out. At least work was never boring when you were a superhero.

He suited up quickly, shucking his pajamas and pulling on the suit, gloves, and cape that he wore in battle. Even after several years, he still thought it was a bit silly to wear a suit into battle. But Reborn had insisted, and as usual, Reborn got what he wanted. At least the fabric was reinforced somehow and actually protected him in battle. He’d asked Verde how they made the suits so durable but the explanation had flown right over his head, so he just accepted it for what it was.

The last item he put on was his mask, the most eye-catching piece to his costume. It was styled like a masquerade mask, covering only his upper face around his eyes. It’s unactivated form was black, but once he put it on it burst into brilliant orange flames, matching the color of his eyes when he used his powers.

Once dressed, his thoughts turned to the mission. Level eight meant a mandatory partner; it was one of the protocols Tsuna had personally pushed for, in an effort to minimize loss of life during missions, both for civilians and heroes. So far, it’d worked well. (There had been a _slight_ snag with finding a partner that Kyouya wouldn’t leave in a broken heap on the ground. He seemed to find Kusakabe tolerable, thank god, and he also didn’t mind working with Chrome if the situation called for it.)

Just because Tsuna was the boss didn’t mean he was exempt. His usual partner was Reborn, both because they had complimentary fighting styles and powers, and also because Tsuna was one of a dozen or so people that didn’t fear him too much to work with him. Tsuna sometimes partnered with Xanxus, but the Varia Commander preferred working with Squalo.

If he remembered correctly, Reborn and Xanxus were both out on missions. It wasn’t really a big deal. After working with those two for so long, Tsuna was confident he could easily work with anyone.

That confidence was shaken when he stepped out of HQ and saw who was waiting for him. He had to make a serious effort not to groan.

“Hi Tsu-chan! It’ll be fun working together today,” Byakuran chirped while bobbing in the air, legs crossed casually and big grin on his face. He was wearing his white uniform with the shoulder guards. (Tsuna had always been suspicious of how he kept it so pristine, even during combat. It was unnatural.) His wings arched elegantly from his back, white as snow and impossible to miss.

Tsuna wouldn’t deny, at least to himself, that the man looked like an angel descended from on high. It was unfortunate he had the personality of a devil.

“Byakuran,” Tsuna nodded to him, attempting to be professional. “I guess Irie partnered us for the mission, then?”

“Mm, looks like it. You’re lucky I was in the area, who _knows_ who you’d be stuck with if I wasn’t here!” Byakuran somehow managed to speak in a bubbly voice while leering, and Tsuna was very disturbed by it.

“Right. Lucky me,” Tsuna muttered.

A rumble shook the earth, followed by a cacophony of car alarms. It didn’t sound that far off.

They both turned towards the disturbance, then each other. For once they appeared to be on the same page.

“I guess we should go do something about that. It’d be too bad if the city was destroyed, then we couldn’t go out for ice cream together after!” Byakuran pouted, seeming upset that their conversation was being cut short.

Tsuna had a _lot_ to say in response to that, but another tremor ran through the ground before he got the chance.

Right. Stop the monster now, tell off Byakuran later.

 

* * *

 

Moments after they left, Irie burst through the doors, panting and clutching his stomach.

“Decimo, I apologize for not finding a partner for you yet, you’ll have to go alone and I’ll send backup as soon as possible,” he gasped breathlessly. When he received no answer, he looked up in confusion, and suddenly had a bad feeling.

Tsuna was nowhere in sight, but more worrying was that he’d just remembered Byakuran had mentioned visiting today. He’d completely forgotten in the rush to find someone to send out with Tsuna.

“Oh no,” he moaned. He was gonna have to break out his XXL bottle of antacids. The one Spanner had jokingly slapped with a label that said ‘For Emergency Byakuran Situations Only’.

 

* * *

 

The fight was going… fine. The monster wasn’t aggressive enough to be an eight in Tsuna’s opinion. It had only made a few perfunctory attacks against them, before returning to destroying things. However, it had incredibly strong armor. Sending anyone weaker would have been pointless, because even Tsuna and Byakuran were having to wear it down slowly. If they could use their more powerful attacks it would’ve been over already, but they had to take into account their surroundings. You couldn’t use an attack strong enough to destroy mountains when you were in the middle of a city. It was tedious, but the civilians had been evacuated, so they didn’t have to worry about someone getting crushed or vaporized or something.

That didn’t mean there was no threat of vaporization, though.

Tsuna growled as another bolt of lightning flew by, missing his face by a centimetre at most. He could feel his eye beginning to twitch as he whirled to glare at his ‘partner’.

“How many times have I told you to be careful where you fling those things?! You almost took off my head just now!” His (very sensible) words were met with laughter.

“Don’t worry, Tsu-chan! I would never do anything to jeopardize such a cute face,” Byakuran _purred_. Tsuna glared harder.

“You know you’re not supposed to use personal names while we’re at work, _Byakuran_ ,” Tsuna hissed. He casually dodged the car hurtling towards him, which had been thrown by the abyssal abomination that was currently trashing the city.

“Aww, but you use mine. Isn’t it only fair I get the same courtesy?” Byakuran fired some more lightning, looking put out when the monster didn’t even seem to notice. It had moved on from destroying the ground to destroying the trees in the city park and seemed content to mostly ignore them.

“ _Everyone_ calls you by your first name. You’ve never kept it a secret, because you don’t care if people recognize you outside of work. Some of us like being able to walk down the street without being mobbed.” While he spoke, Tsuna observed the monster pawing at the ground around a tree to dig away some of the dirt and then ripping the whole thing from the ground. He was trying to figure out what the purpose of it was, but was having no luck so far. It didn’t help that Byakuran kept distracting him.

“But Decimo is such a serious name. Tsu-chan is much cuter, to go with your cuteness,” Byakuran’s cheery explanation was somewhat impeded by the mass of lightning he was raining down upon the monster, now just trying to get its attention. He was unsuccessful.

“Well, being leader of the Vongola is a serious job, so it fits.” He wasn’t getting into an argument about calling him cute, no matter how much he wanted to. He’d already learned the hard way to pick his battles with Byakuran.

“That’s not true. I’m in charge of the Millefiore, and I’m not serious and boring.”

Tsuna snorted. “You sure seemed pretty serious the first time we met.”

In most people bringing up something like that would have them flying off the handle, but of course Byakuran only beamed, and more genuinely than Tsuna had ever seen from him.

“Ah, you’re right, it’s a good thing Tsu-chan was there to save me with his flames of love!”

Tsuna was left spluttering in shock. His eyes felt like they were popping out of his head, and a burning blush was sweeping over his entire face. He opened and closed his mouth a few times, trying to say something, but having no words. It took several long moments for him to regain a bit of composure.

“Th-that’s not what happened! Don’t say it like that, you’ll give people the wrong idea!” His voice was too squeaky for his pride, but at least he’d managed to say something.

“What do you mean? I’m just telling the truth. Tsu-chan’s big, strong flame engulfed me, and it felt so good that it purified my soul. I don’t know how people could get the wrong idea from that,” Byakuran said with a shit eating grin. What an asshole. What an absolute fucking bastard. He knew what he was doing, and he was enjoying it.

“You’re making it sound dirty! It wasn’t a weird sex thing, _I burned you alive,_ ” Tsuna gritted out, still blushing like a tomato and unable to meet Byakuran’s eyes.

Their argument was stalled by the arrival of the monster (which Tsuna had forgotten about, embarrassingly enough) galloping up to them. Its head was on level with them even though they were both two stories up in the air.

They both snapped into fighting stances, bracing for an attack that didn’t seem to be forthcoming. It brandished the tree trunk it had dug up earlier at them, vibrating strangely and seeming to expect something. A shadow near the creature’s lower back was waving back and forth rapidly. The actions reminded Tsuna of something, but he couldn’t place what...

“Is this the abyssal hellscape version of a dog?” Byakuran asked curiously, and it clicked into place. That’s what Tsuna was reminded of, the monster was acting like Jirou when he wanted to play fetch.

“I think he wants us to throw the tree for him,” he said, cautiously approaching. The vibrating intensified, but there was no sign of attack. He grasped the tree trunk and gingerly pulled. It was relinquished immediately, and black shadows along the head seemed to perk up like ears. The shadow-tail wagged harder.

He threw the tree, and the creature made an excited noise and gave chase. Tsuna probably should have chosen a direction with less buildings in the way.

“What are you going to do with it?”

Tsuna hummed, considering his options. “I’m surprised you’re not suggesting we go ahead and kill it as planned. I didn’t take you for a dog lover.”

“I know you would never let me kill something you consider a puppy, Tsu-chan, don’t insult my intelligence,” Byakuran rolled his eyes as he said it, conveying his feelings on the matter loud and clear.

Tsuna quirked a small smile, willing to give him that one. “I think I’ve got an idea for what to do,” he said as he pulled out his phone and started texting.

“Who are you texting?” Byakuran asked, inching closer and trying to read over his shoulder. Tsuna sent the text and turned the screen off, trying to ignore the way Byakuran was breathing into his neck and making him break out in goosebumps.

“I told Spanner to get a minion to deliver a really big leash and some tranquilizers to us.”

“Why do you need tranquilizers _and_ a leash? Surely it’s an either or situation.”

“The tranquilizers are for you,” Tsuna turned and smirked in Byakuran’s face where he was still leaning over his shoulder. Tsuna laughed at the flabbergasted look on his face.

The dog-creature returned with the tree and held it up for Tsuna to throw again. He obliged, throwing it in the same direction in an attempt to avoid further damage to the city. It chased after it joyfully.

Byakuran rallied, and gave him a pout with a hint of smile in it. “How mean, Tsu-chan. How will you make it up to me?”

“Like that could hurt your feelings, I’ve seen people say way worse about you and you didn’t care. Well you did, but in a stabby way, not an upset way.”

Byakuran chuckled, mouthing ‘stabby’ into Tsuna’s neck, making him shiver. He should really push him away, but Tsuna kind of liked the way he was pressed along his back and hiding his face in his neck. He’d never lied to himself about finding Byakuran attractive, he’d just never let him close enough for either of them to act on it.

"That’s different. Other people don’t matter,” Byakuran said in his ear. Another shiver ran down Tsuna’s spine. He had no doubt Byakuran knew what he was doing to him.

And that was a loaded sentence if Tsuna had ever heard one. He had no idea how to respond, so he just said the first thing that came to mind.

“So about that ice cream…” He couldn’t believe he’d just said that. He hadn’t even considered saying yes when Byakuran had mentioned it earlier, but now Tsuna had gone and basically asked him on a date.

“There’s a place in town that serves it with marshmallows! You have to try it, it’s amazing! We can go as soon as we finish here,” Byakuran said excitedly, wrapping his arms around Tsuna’s neck in a hug/stranglehold. Tsuna flailed for a moment before he managed to pry him off, sending a mild glare at an unrepentant Byakuran.

Tsuna turned to look at the dog-creature, taking in it’s massive form, glowing red eyes, the shadows that covered every inch of it kind of like fur, and the gleaming white fangs in its mouth.

“Do you think they allow pets? I’d say we could just drop him off at HQ and then go, but I get the feeling I’ll be stuck answering questions when I bring _him_ home.”

Byakuran finally moved away from his back, instead coming up beside him and joining him in looking at the creature.

“You know, I’m not sure. He’d have to be left outside anyway, he’s bigger than the building.”

“We might have to get the ice cream to go so we can keep an eye on him. He’s so big he can cause a lot of damage just walking around. I’ll have to ask Verde about a way to shrink him so he’ll fit in the base,” Tsuna said thoughtfully.

“What are you going to do with him? You never did say.”

“Mama’s been talking about getting the kids a pet, I figure Natsu will do nicely.” That got a snort of laughter and a raised eyebrow.

“Natsu? What kind of name is that?” Byakuran asked in amusement. Tsuna sniffed.

“It’s a perfectly good name, thank you very much. And see, he likes it.” He pointed to the dog-creature, who had his shadow-ears perked up again and was staring at Tsuna intently. His shadow-tail was wagging.

“There’s no accounting for taste, I guess. Do you think he’ll follow us on his own?”

“Probably. He seems to like us. I guess we’ll just have to see, and come up with some other plan if he doesn’t.”

“Whatever you say.” Byakuran smirked and grabbed his hand, leading him presumably towards the ice cream shop. Tsuna wondered if they would be open, considering part of the city had been destroyed by a dog-creature.

 

* * *

 

They were open, miraculously, and had recognized Byakuran on sight and started preparing his order without him having to say anything. Unsurprisingly, it was more marshmallow than ice cream. Tsuna tried some and had to admit it was surprisingly good. The workers didn’t seem to mind Natsu, who waited outside.

Mama and the kids loved the new family dog. Verde was working on a way to make him fit inside the base.

Reborn, returned from his mission, smirked when Tsuna walked in blushing and holding hands with Byakuran. Tsuna groaned. Reborn was going to tease him relentlessly.

The hand in his tugged him into Byakuran’s side, a warm arm snaking around his waist, and Tsuna had to admit that the teasing might be worth it.

 

 


End file.
